RGM (repulsive guidance molecule) is a membrane protein initially identified as an axon inducing molecule in the visual system (see non-patent document 1). The RGM family includes 3 kinds of members called RGMa, RGMb and RGMc, and at least RGMa and RGMb are known to act through the same signal transduction mechanism (see non-patent document 2). Subsequent studies have clarified that RGM has a function of axon induction and lamina formation in Xenopus and chicken embryos, as well as a function of regulating head neural tube closure and the like in a mouse embryo (see non-patent document 3). In addition to the functions in the developmental stages, RGM is reexpressed after damage on the central nervous system in adult human and rat, and inhibition of RGM enhances growth of axon after spinal damage and promotes functional recovery in rats (see non-patent document 4). Therefore, RGM is considered as a substance inhibiting axon regeneration after damage on the central nervous system. Also, patent document 1 discloses an axon regeneration promoter comprising an anti-RGM neutralizing antibody as an active ingredient.
Multiple sclerosis is a chronic disease wherein myelin (myelin sheath) covering nerve fibers in the brain and the spinal cord is inflamed to cause demyelination, which prevents smooth transmission of neural information, thereby provoking various symptoms such as visual disorder, movement disorder, hypesthesia, disequilibrium and the like. The etiology has not been clarified as yet, and the disease cannot be completely cured by the current medicine. While it is recognized as one of the autoimmune diseases, the detail of the onset mechanism thereof has not been elucidated. For example, non-patent document 5 reports that CD4+ T cells immunologically attack myelin and oligodendrocyte in the white matter of the brain and the spinal cord.